The P3D v1.7 has the same fixes as the FSX v1.7, so there should not be a problem with the battery, like what happened before.

I must admit that I have not tried the V-One gauge in P3D, but the V-One gauge for the 727 (which is now included as a part of the installation of the 727) works in P3D, so I can't see why the 737 one wouldn't.